To get green sonic you must enter the level select and debug code. Then you must choose one¿of the emerald hill zone levels because the code only works in emerald hill zone (1 or 2.)¿When you start the level press B, you will be a ring,then press a 4 times,you will be 4 rings in a row going up or down,you then hold c and right for about 5 seconds,then you go back to the begining, keep pressing a until your the top of a waterfall. You may not see yourself but you are there. Now do the same thing as before, hold c and right for about five seconds. Then press b and you will be green.

While in Debug Mode, create and position a "Transfer Box" monitor. When you hit it and you are Super Sonic, you lose all your powers but stay yellow. Tails looks the same but has invincibility (little stars flashing around him.)
To regain Super Sonic, let yourself get hit, then turn into a ring (press B) and place at least 50 rings on Tails. Exit debug mode (press B) and jump to become Super Sonic with Super Tails as a follower.

Enter Debug Mode then select a stage. Next press B, A (you must have Sonic and Tails on-screen.) When your cursor changes into a ring, paste it on Tails. Repeat this process and you can gain up to 900 rings and several 1-ups.

To hear the Emerald Hill melody (at the title screen), go to sound test selection in the Options menu and listen to songs 1, 1, 2 and 4. Then highlight Player Select and press start. You will hear Oil Ocean at the beginning of the 1st level. Reset the game, and you will hear Emerald Hill!

Enter the level select and debug codes, then go to the Sky Chase level. Using debug mode, create a transfer box and break it open. When you hear Sonic die press B to enter debug mode again. Move the cursor up until you see Tails and exit debug mode. To finish, jump and you will have 2 Tails.

On the last level (Scrap Brain), find the ledges that move right then left. Go to the left side of the wall and wait for the platform to move. As soon as it starts to move left, duck. You will go through the wall. While here, press Left to teleport right and Right to teleport to the left.

First off, do the regular Sonic & Knuckles Level Select. Once that is done, hold UP + A, then put Sonic 3 in and reset the game. When you get to the Sonic 3 & Knuckles menu you will find that Sound Test is there.

Enable Level Select, then press Down to make sure you have the sound test (do not select it yet). Start a one-player game and choose Tails in the Data Select screen. When the timer appears, press RESET.
Enter the Sound Test menu and choose any zone. Hold A and press Start. You should be Tails and be in debug mode. From here press B, then press A until you see a box. Press C to select it, then press B to return to Tails.
To enable Super Tails, jump on the box. Tails will look weird and can not be hurt or lose any rings. He can still get squashed and drowned, though, so be careful in the Ice Cap zone. You will have do this at the beginning of each zone. Robotnik can hurt him at the very end of Launch Base zone-act 2.

In Marble Zone act 3 you will find 3 chandeliers with spikes in them. Go to the far wall (on the right) and jump to the right to find some goodies. Now jump through the wall on the right again, but be careful of the other chandelier.

Enter the LEVEL SELECT code shown below. Go to "special stage" and get an emerald. You will go to Emerald Hill Zone. Pause the game, and press A. Enter the level select again and return to the special stage. Repeat this process until you have all the emeralds.

Enter the level select code and go to a boss. Next push start then push and hold B. You should be playing in slow motion. When the boss enters
the screen get a hit on the boss then let go of B and the screen should be paused. Then press start and there should be no boss music.

Enter the sound test menu choose a level. Look for a star post, touch it and hold A and press START. Then choose another level. If done correctly the title of the zone will change. Beware you might start out in a wall so use debug mode to fly out.

Just before Before you fight Robotnik in the Hydrocity Zone, act 2, the boss music will come. Keep Sonic's head under the shallow water until he is about to drown, then pop out of the water. You will hear the boss music from Sonic and Knuckles.

In Wing Fortress, go as far as you can to the right without climbing. Make sure you have some rings. When you see blades blocking your way, go ahead and hit them. As soon as you are invincible, walk through them. Jump on the platforms to the right and half the level will be finished.

To do this trick you must get to the 1st level of the Launch Base Zone. Set off the 1st alarm, stop Sonic in the middle of it, and do a Spin-Dash attack. The flybots will continue to attack, and eventually their value will increase to 10,000 points! Every five flybots will gain you a life and, if you are patient enough, you can earn up to 99 lives!

Here's a way to play the Oil Ocean music through the whole game. Go to the OPTIONS screen and enter sounds 1, 9, 9, 2, 1, 1, 2, 4. You should hear the Oil Ocean music. Next, hold A + Start and you should return to the SEGA screen with the Oil Ocean music still playing.

If you have Sonic & Knuckles, hook it onto Sonic 2. Play until Chemical Plant Act 1. When you get to the wall with the Spiny badnik and the warp tube on the floor. Break open the tube and go through it. When you come out you will see a Ring Box next to a tower. Climb up the tower and on the top you will find one 1-up. Glide left and you will find another 1-up. Glide to the left one more time and you will find yet one more 1-up. Since you will not want to go through the level again just glide to the right until you get to the tower you started from. Get on that 1st tower and glide to the right. The Act will be over and you will have 3 lives more that how much you started the act with.

This code requires a Sonic 2 cartridge. Insert Sonic 2 and enter the Sonic 2 Level Select (play sounds 19, 65, 09, and 17). Return to the Title Screen, hold A and press Start. To transfer this to Sonic 3, hold A and carefully remove the cartridge without turning off the Genesis. Insert Sonic 3 and press Reset. Finally, release A and press Down twice at the main menu.*** You might notice a few levels you haven't seen before, but you can not select them. Those levels were originally intended for the game, but were pulled in order to release the game on time.

This cheat allows you to start at the First Level with all the Emeralds, and with lots of Continues. Use the Level Select cheat (see above) to get to the Special Zone. When you get the Emerald, and have entered into the First Zone, press Reset.
Use the Level Select cheat to get to the Special Zone again. When you get the next Emerald, and have entered the First Zone, press Reset again.
When you have all the Emeralds, continue on with the
first level. You get to keep the Emeralds and the
Continues accumulated so far.

Start the game as you normally would. Get a Chaos Emerald, reset the game, and start the game from the options menu. You will keep the emeralds you have gained so far each time you start from the options menu.

To become Super Sonic without getting all the Chaos Emeralds, 1st enable the level select and debug mode. When the game begins, create a power-up box. There should be an 'S' on the box. Jump on it to grab 50 rings and become Super Sonic!

Use the Debug Mode code in Launch Base act 2. Win the game. When Sonic or Tails jumps towards you, activate Debug Mode and get out of it immediately. You will be able to use Sonic or Tails in the background for a short time, but they will look like robots.

To become Super Sonic without getting all the Chaos Emeralds, 1st enable the level select. At the level select menu, go to the sound test item, and play sounds in this order: 4, 1, 2, 6. You should hear the music you get when you win a chaos emerald. Now select any level, get 50 rings, and jump.

To gain all the chaos emeralds, enter the Level Select code, then highlight "Special Stage" and press C + Start. After receiving the emerald, press A + Start and repeat the process until you have them all.
Alternatively, enter the Sound Test code and play sounds 2, 4, 5, 6 in order. If you did it correctly, the Emerald sound will play.

Go to the one player mode when sonic and tails pop up on the screen ready to play you will notice that if you run tails follows. If you add an extra control in port 2 and press a button and bingo you can play the whole game in 2 player mode. Unfortunately there are no scores for tails and no life limit.

Use the debug mode cheat. Start any level that has a special stage ring. Next turn into your favorite object. As an object go to the center of a ring. Now hit B twice quickly. When you get out of the special stage you will look like that object for the rest of the level.

Start Mushroom Hill as Sonic. Run to the right until you come to the 1st Pull-Up machine. (It's just after the box with the power sneakers and the Madmole.) Hang from it and press left left left, right right right, up up up. You should hear a ring sound. [Pause Game] and press A to reset to the title screen. Now hold A and press start for level select.

Go to the level select screen and play tunes 1,9,9,4,1,0,1,8 (the date when the game was made.) Choose any level, then hold A and press Start to activate Debug mode. To use it, see the instructions in Sonic the Hedgehog.

From the Title Screen, hold A then press Up, Down, Left, Right. When you hear the chime, press Start. If that doesn't work, try this: at the Title Screen, press Up, Down, Left, Right, hold A, and press Start. After doing this once, you only need to hold Start + A to enter the level select.

From the Title Screen, press Up, Up, Up, Down, Down, Down, Left, Right, Left, Right. You should hear a ring. Next, press A + Start to enter the Stage Select screen. This code will remain in effect until you turn off the Genesis.

First go to Angel Island Zone and, while on a vine, press Left, Left, Left, Right, Right, Right, Up, Up, Up. If it has been entered correctly, you will here a chime. Then press Start then A. At the Title Screen, scroll down to Sound Test and press Start. At the Sound Test screen, go to Mushroom Hill Zone and press Start. While on a ratchet machine, enter the same code you entered in Angel Island. You should here a chime. Again, press Start then A. At the Tiltle Screen again scroll down to Sound Test. At the Sound Test Screen select a zone while holding A. Hold until the name dissapears. You can check if you are in Debug Mode by pressing B. Your score should turn into hexadecimal characters. The controls are these:
With Debug Mode on:
A- change sprite
B- disable Debug Mode
C- add sprite

To enter Debug Mode, play these sounds from the level select screen: 1, 9, 9, 2, 1, 1, 2, 4. Press Start and hold A.
To start debugging, press B, then you can select any sprite in that level and put it on the screen. To select a different sprite, press A, and to place it on the screen, press C. Note that sprite selection is different from Zone to Zone. Also, instead of displaying the time elapsed, it displays the number of sprites currently on the screen.

Enable Control Mode. After pressing Start to begin a game, hold A until you see Sonic. If you see a bunch of hex numbers on the top of the screen, you are in Debug Mode.
To start debugging, press B, then you can select any sprite in that level and put it on the screen. To select a different sprite, press A, and to place it on the screen, press C. Note that sprite selection is different from Zone to Zone. Also, instead of displaying the time elapsed, it displays the number of sprites currently on the screen. Control Mode functions work as well.*** This only works on the 1st production releases of Sonic.

Start Mushroom Hill as Sonic. Run to the right until you come to the 1st Pull-Up machine. (It's just after the box with the power sneakers and the Madmole.) Hang from it and press LEFT, left left, right right right, up up up. You should hear a ring sound. [Pause Game] and press A to reset to the title screen. Now hold A and press start for level select.

Connect your Sonic & Knuckles cartridge to Sonic 3. Activate the level select and debug. When you enter debug mode, create a monitor. It will have an "S" on it. Jump on it to get 50 rings and become Hyper Sonic, Hyper Knuckles, or Super Tails!